


Who Knew That Triangels Were Sex Gods?

by Crappy_fanfic_writer



Category: Gravity Falls
Genre: 19 or smth, Aged up dipper, Bill has some kind of cosmic vagina, Bill is not going to be a complete asshole in this, Bill is smol and insecure, Bill will be a little OOC at times to fit the needs of the story, Blood As Lube, Dipper too, Established BillDip, F/F, First stab at tentacle porn, Ford never came through the portal, Ford will be a part of this story and comes in in chapter 6, Going to Hell for this, Happy Forrest Mindscape Sex, He’s like, Human!Bill, I am, I guess., M/M, Magical Bondage, Mature!Dipper, Mpreg, NSFW, Period Sex, Porn, That’s it for now, There will likely be tentacles in some way shape or form, This is a sin, You know what I’m not done, and because I need more healthy relationship BillDip, bottom!Bill, first work in this fandom, macifica, plus Dipper and Bill being sappy dorks is my favorite thing, this is gonna be a ‘Dipper and Bill take over the world’ story, this is gonna start as a one shot but I’m usually terrible at that so we’ll see where it goes, triangle!Bill, with smol demon children
Language: English
Status: In-Progress
Published: 2015-10-27
Updated: 2016-04-05
Packaged: 2018-04-28 10:43:54
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 6
Words: 10,806
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5087650
Author URL: https://archiveofourown.org/users/Crappy_fanfic_writer/pseuds/Crappy_fanfic_writer
Summary: <blockquote class="userstuff">
              <p>Bill and Dipper have been friends for a while now (after Bill started hanging around waiting for the moment to execute his master plan.), and have recently started…Dating? Can one even date a small, immortal, isosceles triangle from hell, who wants you to become his immortal consort before taking over the world together? Apparently you can. Follow Dipper and Bill through this ridiculous roller coaster of supernatural events, dealing with family, and world domination.</p><p>Bill and Dipper met in the same way, but the sock puppet fiasco never happened. Instead, Bill just got Dipper to make him a fancy gold pyramid suit out of this fancy supernatural material to possess, and he just sorta hung around, befriending Dipper with knowledge of the supernatural and it lead to fluffy and angsty things that will not be revealed until later on.</p><p>THIS WILL HAVE A WEIRD POSTING SCHEDULE UNTIL SCHOOL CALMS DOWN WHICH MIGHT BE NEVER BUT I'LL TRY</p>
            </blockquote>





	1. Almost a Prologue, But Not Quite

**Author's Note:**

> Yay!!! Shitty thing I wrote in the middle of the night cuz my brain decided ‘hey there’s not enough Triangle!Bill porn out there! Let’s go write a shitty thing!!!’ so this happened. Also apparently I do my best writing at god awful hours of the morning and it ends up being either really well written or so cracky I have to re write it, so I hope I can get this done in a semi timely manner.  
> Also! I would love some Constructive criticism on that smut scene for two reasons: One is that this is my first time writing demonic frick frack and I have no clue what I am doing outside of what I have read, so any kind of NICE commentary/feedback is really welcome on that front, Second! I would love to hear what reader’s want to read about, because I started this because I wanted more Dipper fucking triangle Bill, so if you have any ideas of what you want to read, I’d be glad to hear it, and it might show up if I can fit it in.

Dipper was walking through the forest. This was a daily tradition for him, as well as it was usually the only alone time he ever got, and even then, his ‘Dipper Time’ was sometimes interrupted by Bill. Though, if Dipper was completely honest with himself, he never really minded whenever Bill tagged along (Even Mable got along with Bill, though Grunkle Stan was still way to apprehensive of Bill to even consider spending time with him alone and Dipper could kind of see why. Bill was a lunatic.). As long as he didn’t bring Dipper a bag of deer teeth, or a screaming head. Again. Stupid demon. Dippers’ favorite thing was when Bill decided to come along, and they just walked (or, in Bill’s case, floated.) side by side, and were silent or talked of nothing in particular. Though Bill was usually his classic sarcastic and morbid self, Dipper found that he really didn’t mind much. He had seen way too much to be bothered by Bill’s comments about how to disembowel a small deer or buck in under 20 minutes. Even hearing about Bill’s plans to take over the world didn’t bother Dipper anymore. He even helped with some of the strategy parts. Honestly, if Bill wanted to, Dipper would probably let him do his world takeover thing, and help (more), as long as his family didn’t suffer. 

“FUNNY you should mention that Pine Tree!”

Dipper jumped when the echoing voice of Bill Cipher boomed throughout the forest. Of course he was listening. Bill was always listening and Dipper almost hated it. 

“What do you want this time, Bill?”

Dipper sighed fondly, rubbing his eyes. Bill materialized his glowing isosceles form in front of Dipper, twirling his cane on his arm.  
“WELL to start, I want YOU, DIPPER PINES, to TAKE OVER THE WORLD WITH ME and become my IMMORTAL CONSORT. Any objections? Because you will essentially become a demon yourself.” Bill loudly exclaimed.

Dipper sighed. He was expecting this would happen at some point, just not this soon, He wanted to get Mabel and his Grunkles, especially Ford, used to the idea of him dating a dream demon form hell BEFORE springing the ‘Hey I’m gonna take over the world with my demonic boyfriend!’ on them, because despite them not quite understanding his decisions, they were his family, and he didn’t want them dead. But what’s the catch?

“The CATCH, my dear Pine Tree, is that YOU have to BIND YOUR LIFE FORCE TO MINE so that you will NEVER die.” Bill said.  
Wow. That really wasn’t all that bad. Dipper thought it was going to be something like ‘you need to murder 3 virgins’ or ‘kill some random creature in Gravity Falls’. Though Dipper did have one more question.

“And what do I get out of it Bill? It’s only a deal if both parties are interested.” Dipper mentioned casually, fully intending to take the deal either way, but he wanted to see what Bill had to offer.

“I’M GLAD YOU ASKED, PINE TREE! Once you have BOUND YOUR LIFE TO MINE FOR ALL ETERNITY, you will be able to ACCESS MY ENERGY and ACTUALLY BE ABLE TO USE MAGIC. Eventually. I’ll have to teach you but YOU’RE SMART so you should CATCH ON pretty quickly,” Bill said, watching Dippers jaw drop in amusement. His human really was fun. “So! What do you say, Pine Tree?” Bill said, holding out his hand which was engulfed in blue flames. “Do we have a DEAL?”

Dipper held up a hand in the universal cue to ‘hold your horses, I have one more goddamned question’. “Just one more thing. What will I have to do to become your ‘immortal consort’ Bill? What will happen?” Dipper asked.

“WELL, it’s ACTUALLY a lot SIMPLER than people think, Pine Tree. All YOU have to do is donate about 10 mL of your BLOOD, then let me worry about the rest. Souls are finicky, kid. They’re not something that you can work with without practice. THAT will come later.” Bill explained. Dipper nodded. It made sense. Dipper held out his hand.  
“I guess you have a deal, Bill Cipher.”

 

OoO~~2 Weeks Later~~OoO 

 

Dipper and Bill were slowly walking (or floating) hand in hand back to the Mystery Shack, not so eagerly awaiting the large talk that they’d probable get from Mable and Grunkle Stan for being out until 10:30 (and for Dipper looking like he just burned the whole forest to shit while standing in the middle of it all, which he did, but that was beside the point.).Dipper was finally starting to have some functional ability with this magic shit (After having bound his soul to Bill’s life force, which was a lot less painful then Dipper would have thought, and the process was really cool, in Dipper’s opinion). Where at first, he could barely conjure a small flame in his hand, now he could burn whole circles of the forest with barely a thought. Now Bill was talking about starting him on illusory magics, and after that, transformative magics. It all sounded quite fun to Dipper (who had absolutely no qualms about almost being charred to a crisp in the forest, since Bill had mentioned that before starting with the illusory magic, Dipper would need to teach his flames to not burn him, but that should be easy, since he already had such good control over them. He just needed to beat a little submission into them.)

As it turned out, they didn’t actually have to worry about Mable and Grunkle Stan. Mable had left a note saying that she was staying at Grenda’s house with Candy and Pacifica (though it was a wonder Mable got her to show up), and Grunkle Stan was going to be out late drinking (gambling) and wouldn’t be back until ass-o’clock in the morning.  
Grateful for some down-time, Dipper collapsed onto Grunkle Stan’s recliner, while Bill shrunk himself down and made a nest in Dipper’s hair. Dipper still had yet to figure out why Bill did this, but it was cute, as well as comfortable, so Dipper wasn’t going to complain.

Dipper ended up watching old reruns of Duck-tective until the program changed, then he started the slightly precarious trek up to the attic bedroom that he and Mable still shared, for lack of a better sleeping place. Bill was so preoccupied with braiding three lone strands of Dipper’s hair together, that he didn’t notice Dipper had moved until he was being poked.

“Bill, unless you want to be drenched in hot water, I strongly suggest that you move.” Dipper said.

Bill grumbled, stood up on all fours and turned in a circle on Dipper’s head, before settling back down and continuing to play with his hair. Dipper just shrugged and rubbed Bill’s back with a finger (Bill’s edges might be fun to play with when he’s normal sized, but mini-Bill was like a paper cut waiting to happen). Bill just made a rumbling noise. Almost like a purring cat. Dipper found it really cute whenever Bill did it, which was never very often. 

Bill went back to grumbling as soon as Dipper stepped under the spray of water. Dipper had always wondered why Bill disliked water, but the one time that he had asked Bill about it, he got a vague, half answer, so Dipper didn’t push it. One thing Dipper knew for a fact was that Bill liked was shower sex. Apparently Bill thought that Dipper was sexy when he was wet. Once Dipper had figured this out, he exploited it for all it was worth. And since there was no one home tonight, it was a perfect opportunity.

Dipper grabbed the soap and began lathering it over his body, sensually moving his hands over his body. Dipper focused most on accenting his hips, crotch, and ass. Dipper could feel Bill moving forward on his head to sneak a peek. Bill floated down in front of Dipper, returning himself to his regular size.  
“What are you playing at, kid?” Bill asked.

“Nothing, Bill. Just thought that you might enjoy a little show, that’s all.” Dipper said, moving under the spray of warm water to wash the soap from his body. Bill’s body starts to turn a little pink at the mention of ‘a little show’. Dipper turns around to face Bill, funning his hands up and down one of Bill’s sides. Bill shudders. More like he vibrates, but fuck it, Dipper thinks, the word fits.

“You up for a little fun, Bill Cipher?” Dipper asks.

“Am I? Kid, you sure ask the DUMBEST questions. I’m always up for WHATEVER you have in MIND.” Bill says, snapping his clawed fingers, drying Dipper, teleporting them into Dipper’s room, and onto his bed.

With that, Dipper grabbed Bill, and put the small triangle in his lap, caressing his sides, while Bill, ever so kindly, ground down on Dipper’s dick. Dipper hummed. He was interested to see if sex with Bill was different now that they had been bound. Though, given the situation, Dipper guessed that he would find out pretty soon.

Dipper was pulled from his brief period of thought by Bill impatiently grabbing his hand and moving it between his legs to the opening that seemed to only be present when Bill was aroused. Since the surprisingly fleshy opening was present in the small triangle, Dipper thought that he was doing a reasonable job of pleasing the demon.

Bill let out a breathy sigh when Dipper pushed his fingers into Bill’s small opening. Dipper still, after so many times, could not believe how warm Bill was on the inside, compared to the cold exterior that Bill preferred. The difference in personality that Bill displayed when talking with others as opposed to Dipper was startling. If Dipper didn’t know that the demon liked to wear a mask formed of little emotion and quite a bit of hatred, then he to, would be filled with confusion when the demon was even remotely kind or generous. However, Bill had demonstrated a lot of both over the years that Dipper had known him; showing Dipper more of the secrets of the forest surrounding Gravity Falls, most of which were not included in the Journals, as well as showing him many comfortable resting places to escape from the hectic life that is working in the Mystery Shack. Bill gave him non-lethal flowers that could not be found in any other place but the forests surrounding the sleepy town; on one occasion, going so far as to give Dipper a flower that would connect their fates. For a being of pure energy with no weakness, Bill sure was insecure.

“I heard that Pine Tree.” Bill grumbled. “Now, let’s see how FAST I can hop on that PRETTY LITTLE DICK of yours, shall we?”

Dipper nodded his ascent. Sex with Bill was always interesting. Sometimes it involved bondage with fire, other times it was perfectly vanilla, aside from the fact that they were floating above Dipper’s bed (Mindscape sex was almost scary with the amount of tentacle that were usually present.). Though today, it seemed that Bill had settled on something relatively vanilla for their standards: teleportation. Teleportation sex consisted of Bill teleporting himself on and off of Dipper’s cock at slightly worrying speeds, then riding him for a good while, repeating this until they both came. It was really good for teasing and orgasm denial. Dipper wondered which one Bill would choose tonight.

“Ahh!” Dipper moaned as Bill phased himself into existence on Dipper’s dick, then quickly departed again, repeating every second. Looks like Bill decided that teasing would be fun tonight, though Bill seemed to give up on the teasing after only a short while, deciding instead to ride Dipper to completion.

Dipper arched his back when he felt Bill clenching whatever sort of cosmic vagina he had around Dipper’s cock. Apparently it did something for Bill too, because the action was repeated, Bill still moving up and down on Dipper’s member, clenching slowly increasing in speed. Dipper started to feel a familiar heat curling in his stomach.  
“B-Bill-AH! Gon-gonna cum!” Dipper managed to say, despite the pleasure crowding his mind. 

Dipper managed to last a good 3 seconds with Bill clenched around his dick before he was cumming. Bill clenched around Dipper’s cock once more before his… whatever fluttered.  
“Mmmmm. That was a lot less KINKY than I had planned.” Bill said; casually sitting on Dipper’s crotch, with cum slowly dripping out of his… space pussy? (What do you even call something that a small demonic triangle can magically materialize on his person? A magic strap on? A plain old vagina? Dipper had yet to gather the courage to ask Bill about it, so for now, it’s a demonic vagina.) Though Dipper really didn’t know what he had been expecting from Bill. 

Dipper sighed. “Damn it Bill!”


	2. Chapter 2

**Notes for the Chapter:**

> this is where that Mpreg tag starts to come in, so be warned, I also read a prompt that made me want to change up the plot a little, so now we have human Bill thrown into the mix  I will also TRY to update once a week, but depending on how school is, and what my personal life throws at me, that might not happen. Lots of self-indulgent fluff in this chapter.

Dipper and Bill had a relatively peaceful sleep. Aside from the raunchy tentacle sex, which consisted of Bill conjuring blue fire tentacles and fucking Dipper with them for excessive amounts of time. Bill found this terribly fun so Dipper ‘put up with’ the teasing.

However Dipper’s favorite thing was probably the cuddling that Bill ‘put up with’ for him. Since Bill was an isosceles demon form hell, cuddling usually consisted of Dipper leaning against the headboard of a bed or the couch, with Bill laying on his chest or sitting in Dipper’s lap. Sometimes Bill teleported Dipper into a field and sat on his chest and they gazed at the stars together.

On this particular night Bill had decided that star gazing was a good thing, so Dipper was now lying in a field of ‘Bill Cipher Deals’ blue forget me nots looking up at a sky filled with stars, listening to Bill tell his favorite myths about said stars.

“You know, Pine Tree, a lot of constellations have ROMANTIC LEGENDS associated with them. Take THE SWAN one. The Greek legend for that one is that Zeus wanted to SEDUCE the goddess Nemesis, so he turned himself into a SWAN and had the goddess of LOVE, Aphrodite, chase him into her lap. Or CASSIOPEA. She was the daughter of a woman who claimed that she was more beautiful than the Naiads. For this BEAUTIFUL INJUSTICE TO THE GODS she was CAHINED TO A ROCK, set to await death by a SEA SERPENT, but some hero came and stole her away, so Zeus put the WHOLE FAMILY in the sky as a reminder to never compare one’s self to a god. But hey, pretty boy sure did love that chick if he was willing to defy IMMORTAL BEINGS. Plus, a lot of these legends stem from DEMI-GODS. Wonder if we could make little HALF-DEMONS? That would be ONE HELL OF AN ADVENTURE, huh, Pine Tree?”  
Dipper snorted (Of course Bill would think that gods killing whole families was romantic.). “Yeah. Wait, how is that even possible? I’m a guy, and you’re some kind of cosmic dream demon.”

“Sweet innocent Pine tree. You know that I am a BEING OF PURE ENERGY WITH NO WEAKNESS. It wouldn’t be a stretch to alter my form or yours, for that matter, to be able to carry a child of some kind. Besides. How HARD could it be? Women have been doing it every day for MILLENIA, mostly without PAIN KILLERS too. Plus; PAIN IS HILARIOUS!”

Dipper laughed quietly as Bill rambled on about the pros and cons about having a smol (Yes, Bill did in fact use the word ‘smol’.) kid running around the shack. Apparently they could teach it how to prank Stan, use magic, and how to be a good little half demon. Dipper had to admit that it would probably be nice to have a little him, or even a little Bill running around Gravity Falls, uncovering the mysteries of the sleepy town for themselves. They could teach it to hate Gideon too. Though he didn’t know how he, or Bill, for that matter, would be able to deal with the hormone imbalance that came with pregnancy. Not to mention the fact that Dipper was a guy, so he had no experience whatsoever with any kind of estrogen, and Bill was a demon from another dimension entirely, so he had absolutely zero experience with human hormones anyways, not to mention the imbalance that came with pregnancy. Dipper questioned how either of them would ever feasibly survive that. And how would the baby…come out? Would Bill magic it out? Or would it get magically…craped out? Or was that part of what Bill meant about altering his form? Dipper had no fucking clue. This whole thing raised way too many questions and…wait…had Bill said that he could alter his form? Dipper knew that Bill could adjust his size to fit his desires, but what sounded like a complete alteration of form? Dipper never knew that Bill could do that.

“There’s A LOT that you DON’T KNOW about me YET, Pine Tree. As for CHANGING MY FORM, I can make PRETTY MUCH ANYTHING I want to. I can do MALE with FEMALE parts, or FEMALE with MALE parts, or ANY KIND OF MONSTER YOU CAN THINK OF! Even a NORMAL HUMAN, though that’s no fun.” Bill pointed out.

“I never said ‘yes’ you know.” Dipper reminded the over enthusiastic demon.

“But Pine Tree! BABIES!” Bill said, floating up in front of Dipper’s face.

“Bill, do you even know how human baby making works? Yes, the MAKING is fun, but the actual pregnancy? That comes with a shit tone of hormones, weird cravings, and achy everything, not to mention the morning sickness. Now, I don’t know how demon baby making works, or if you guys even do that, but human pregnancy is awful. I would not be adverse to us having a baby. I think it would be cute and fun, but why don’t we just adopt?” Dipper said.

“BECAUSE, Pine Tree, ADOPTION takes FOREVER. Pregnancy takes a MEASLY NINE MONTHS. Plus HOWEVER LONG it takes for one of our bodies to deal with the new organs, but that won’t take more than TWO OR THREE MONTHS, plus CONCEPTION RATES, but those are usually PRETTY HIGH for demons, so that SHOULDN’T BE A PROBLEM.”

Bill really did seem too want a kid. But why? In the years they were together Bill had never mentioned kids. Ever. Not even when Mable and Pacifica started to think about Invitro fertilization for after Mable finished college, so what brought this on? Was demon breeding season coming up or was Bill just genuinely interested in expanding their weird family? And what would kids do to Bill’s plans for Gravity Falls?

“WELL FOR STARTERS, I don’t plan on enacting any PLANS until you have more of an OFFENSIVE AND DEFENSIVE FORCE built up, then IF we end up with ANY NUMBER of tiny people under our care, those kinds of PLANS would have to wait another… 14 years? So that the kid or kids can build up their own power, THEN we’d need access to that portal in your basement (Dipper and Mable had caught Stan sneaking into the basement towards the end of their second summer in Gravity falls and had gotten the full story, though Stan had yet to complete fixing the portal.) so I can KILL Time Baby BEFORE he takes over the world, then I just manifest in the physical plane and bend the whole of Gravity Falls to my will. Kids won’t really change anything. Just slow it down for about a decade. Not that long when you’re AN IMMORTAL BEING, eh Pine Tree.” Bill said, answering one of Dipper’s questions.  
“Ok Bill. That makes sense, but you haven’t answered the ‘why now’?” Dipper stated, looking Bill in his eye.

Bill’s eye widened, images of him and Dipper arguing or Dipper getting mad at something silly the dream demon had done flashed across the surface of Bill’s triangle. “Well…Ummm…You see, Pine Tree…I…” Bill seemed to glow a light pink, his eye darting around the mindscape forest, not wanting to meet Dipper’s constant gaze. Bill sighed, then looked determinedly at Dipper. “Humans have kids with people they l-love, right? People who they want to spend their life with? W-well I…I want to be able to do that with you, Pine Tree.” Bill said sheepishly. “That, and I was ALMOST worried that you would leave after I finished instructing you on the workings of magic.” Bill admitted.

Dipper felt genuine surprise at that statement. Bill showed a lot of affection physically, and through small (or not so small) gifts (one time Bill had brought Dipper an entire deer corpse. The little shit had left it on the floor by Dipper’s bed. That was when the discussion of human customs came into play. For a demon who claims to know everything, he sure has a lot to learn.), but almost never through words. To have Bill essentially come out and say that he loves Dipper was as rare as a blue moon on a cloudy night.

Bill floundered in the air, waiting for Dipper to respond to his statement.

Dipper responded by grabbing the small floating triangle and crushing him to his chest in what Mable sometimes called a ‘Great Big Dipper Hug’.

“’Course I’ll have kids with you, you dumb Dorito. Though you know that I’d spend life eternal with you anyways, right? Kids or no, I will not leave. If I do, you have the right to poke around in my head to see if Gideon or some other shit messed with my mind, because it’ll take way more than you dicking around to make me want to leave.” He told Bill. “But you’re carrying the first one.” Dipper continued.

Bill mumbled something into Dipper’s chest in response, wrapping his small, black arms around Dipper’s waist as much as he could.

The next thing Dipper knew, Bill seemed to invert his whole body and they were back to staring at the stars.

 

OoO~~3 Days Later~~OoO

 

Bill had been gone for roughly 5 hours at this point. There were 10 hours left before Bill was done with his body construction. Bill had started at 11:30. It was 4:30 now, and it will be 2:30 when he’s finished. Dipper couldn’t wait to see what Bill decided to do with his appearance.

 

OoO~~10 Hours Later~~OoO

 

10 hours and 15 minutes later Bill Cipher walked up the stairs of the Mystery Shack to the attic room that Dipper Pines slept in (Unbeknownst to said Bill Cipher), waiting for him.  
Bill threw open the door with a bang and a shower of glitter, startling Dipper awake. Dipper, being the clumsy, paranoid person that he was, tried to jump into a stand, but missed spectacularly and landed on his face. 

Bill laughed, sharp teeth catching the light of the glitter.

“Jesus Pine Tree! I didn’t think that you’d have FALLEN ASLEEP! Usually you can go DAYS without sleeping. But hey! What do you think of my VERY OWN PERSONAL MEATSACK, Pine Tree?” Bill asked.

Eager to hear what his boyfriend thought of the design, Bill jumped up and down (reminding Dipper of Mable whenever she was particularly excited about something), and brushing two toned blonde and black hair out of his eyes, which were a bright gold, with arms that looked like they had been tattooed black. Bill had, of course, forsaken clothes of any kind, because who would, when they had a perfect partner to try human style sex with. Bill also thought that it would be funny to watch his Pine Tree get flustered by his nakedness. He was not at all disappointed. As soon as Dipper noticed that Bill had no clothes on what so ever, he covered his eyes, and Dipper felt his face go red (simultaneously hoping that this was all some kind of weird dream and that he would wake up to find Bill in some kind of black and yellow get up, as well as that the sound of Bill throwing open the door hadn’t woken Stan up, because Dipper did not want his Grunkle walking in on Bill’s naked ass and jumping to conclusions.).

“Bill! What are you doing?!” Dipper whisper-yelled. “You’ll wake up Stan!”

“And that would be a bad thing WHY, Pine Tree? It would be funny to give the OLD MAN a good scare! And you still haven’t ANSWERED MY QUESTION! What do you think of my MEAT SUIT?”

It was then that Dipper looked at the body that Bill had made for himself and actually took notice of the differences (many of which were QUITE obvious). Bill was now a human of around 6 foot 1, as far as Dipper could tell, with lightly tanned porcelain skin, and blonde hair cut short so that you could see the close cropped black hair underneath. Bill had gold eyes, framed by thick lashes, and a spattering of black freckles around his nose and cheeks. This lead Dipper to look at the arms and legs that bill had apparently died completely black, with small triangles fading the black out into Bill’s torso and upper thighs. Bill had also apparently elected to go with the female reproductive organs, as he did not have a cock hanging between his legs, but was instead sporting a dusty pink vagina. All in all, Dipper was VERY appreciative of it.

“You did good Cipher. You look damn hot in that meat suit of yours.” Dipper assured Bill.

“So… You wanna take it for a spin?”

“Damnit Bill!”


	3. Chapter 3

**Notes for the Chapter:**

> ok so yes this is late, but school has been tough right now because of midterms. And now my tablet that I do most/all of my writing on is fucked up, so I don't know how often I'll be able to update this :( sorry.

Dipper and Bill did, in fact, ‘take it for a spin’. Make outs on the floor (“Ohhhhh. So that’s why you humans kiss!”) Quickly lead to Bill teleporting them all of one meter onto their bed.  
“Really Bill? Was that really necessary? We weren’t even a foot away!”

Bill didn’t bother to correct him. “Shhhh Pine Tree. Less talk, more sex.”

Bill pushed Dipper down onto the bed, catching his lips in another searing kiss. Said kiss lasted much longer than either of them originally intended, both grinding down on each other, seeking more friction than was readily available in their current position. Dipper broke the kiss first.

“So…hah… how do you want to do this Bill? It’s your first time in this body; are we gonna go vanilla, us kinky, or normal human kinky?”

Bill paused to think about this question for a grand total of 3 seconds before declaring his answer.

“Let’s go vanilla tonight Pine Tree. I wanna see what NORMAL HUMAN SEX IS LIKE.”

Dipper sighs. When he first pictured the relationships that he’d have, having a partner that doesn’t engage in ‘normal human sex’ with him was not at the top of the list. Though if Dipper was honest, after he came to Gravity Falls that first summer, he had wondered whether he or Mable would end up in a relationship with some kind of supernatural creature. Now Dipper’s about to have ‘normal human sex’ with the dream demon who almost cost them the shack that one time. At least possession was never involved. That would have sucked. Right now though, there were more important things to consider. Like who was gonna top this time ‘round.

“Hmm. I don’t know Pine Tree. Should I ride you into oblivion, or are you gonna plough me into the mattress?”

Dipper considered Bill’s offer of fucking him into the mattress. On one hand, he could fuck his demon boyfriend who has a hot new body, but on the other hand, Dipper was already on his back and Bill had the power to magic off clothes. The decision was obvious.

“I dare you to see how fast you can take our clothes off without getting off me, then I want you to get on my dick and, to quote a person, ‘ride me into oblivion’.” Dipper told Bill.  
All Bill had to do to fulfill the first part of Dipper’s statement was snap his fingers. In half a second they were naked on the bed and ready to begin with a bottle of lube appearing on the nightstand. Bill moved to kiss Dipper, reaching for the lube at the same time. Bill liberally coated his fingers in lube before slipping them down between his legs to fondle his human vagina. Bill startled, finding himself already coated in a wet substance that was probably not normal. He poked Dipper.

“Dipper! I’m leaking! From my lady bit! That can’t be normal, can it?” Bill frantically grabbed Dipper’s hand, shoving it between his legs, worried that he somehow screwed this whole thing up really badly, that Dipper would hate him. He hung his head, sniffling a bit, feeling tears well up behind his eyes (this he knew was normal. His Pine Tree had had nightmares where Gideon or some random monstrosity of Gravity falls had killed Mable or Stan (sometimes even him) and he had woken up screaming with that same salty water streaming down his face, so Bill didn’t freak out about this one.), silently awaiting the inevitable order to leave and not come back.

Dipper just sighed. Maybe he should have given Bill a female anatomy lesson before this.

“Bill, human females produce natural lubricant when they’re aroused. They evolved that function to facilitate breeding. This is completely natural.”

Bill looked up at Dipper with watery eyes. “You mean I didn’t fuck this up? You don’t hate me?”

Dipper placed his hands on Bill’s cheeks, squishing them together, and wiping a tear from his face.

“You silly demon. No, you did not fuck up, and even if you did, I could never hate you. I probably should have told you about the way humans have sex before all this anyways.” Dipper quietly reassured Bill, pressing chaste kisses on Bill’s lips, forehead, cheeks, and eye lids to calm him down.

It was this particular moment that Bill discovered that hormones suck. He, the great Bill Cipher, Master of the Mindscape, could not stop himself from wrapping Dipper in his arms and quietly crying into his shoulder, relief flooding through him because Dipper didn’t hate him. 

Dipper silently accepted the hug, letting his partner get used to the human hormones that were flooding through his system. They stayed like that for roughly 7 minutes according to the clock on Dipper’s bedside table, just hugging and crying, Dipper comforting Bill until he was ready to talk. Or at least continue where they left off (Bill never was one for heart to heart talks, especially after a period of emotional turmoil, but any kind of physical affection usually meant that Bill was as emotionally stable as he could get. On one memorable occasion, when Dipper had almost gotten himself killed by an angry Gremlobin, Bill sulked behind the Sascrotch for a week straight before presenting Dipper with a bracelet made of dried deer intestines and teeth from the same deer as charms, before engaging in marathon sex that led Mable to stay over at Pacifica’s for the next 24 hours, while Grunkle Stan hid down in the bunker underneath the shack until Mable was forced to convince him that Dipper and Bill were done with kinky sex for a while.).

As it turned out, Bill was largely done with weird human emotion shit, and fucking Dipper’s brains out was just the thing to get it out of his head.

Dipper and Bill spent the next while kissing and grinding, building the mood up again after that emotional fiasco. Between a hormone riddled dream demon and a 20 year old human, it didn’t take very long. Dipper and Bill were soon right back where they left off, only this time Bill didn’t freak out when he was already wet.

Bill merely sunk down on his own fingers, moaning all the way, enjoying the feeling immensely.

Dipper watched on in awe of the faces and small noises Bill made as he stretched himself.

Bill quickly moved on to two fingers, scissoring them a little. After three of his fingers were pumping and twisting inside Bill, he figured that it was enough stretching to accommodate Dipper’s dick, so he took it in his hand, and sat on it, sinking down without pause.

Dipper groaned at the feeling of Bill slowly sinking down on his cock, finding relief after having watched Bill make faces and sounds erotic enough to make the activity that took no longer than 5 minutes feel much, much longer. Then, Bill MOVED; rising up and sinking back down at a steady pace, slowly speeding up, Dipper jerking his hips up to meet Bill half way, keeping time with the pace that Bill had set.

Dipper soon found his hands wandering; one sliding up to Bill’s chest to fondle his nipples, eliciting a gasp from the demon, the other moved down to look for something that he had only read about.

Bill nearly screamed, telling Dipper he had found what he was looking for.

“Holy fuck! D-do that AGAIN Pine Tree!!” Bill said, grasping at Dipper’s shoulders.

Dipper nodded as much as he could, continuing to stimulate Bill’s clitoris, feeling Bill start to flutter around him.

“Ah! S-shit Pine Tree. I’m CLOSE.”

Dipper nodded, the fluttering of Bill’s vagina around him bringing him close to the edge as well.  
Dipper pressed down on Bill’s clit hard one more time, eliciting a cry of pleasure from Bill as he came, and the clenching around Dipper pulling his own orgasm from him as he almost aggressively thrust up into Bill one final time before both collapsed on the bed, panting and ready for sleep.

After cleaning up, of course (Bill was extremely adamant that he was not going to sleep with Dipper’s cum leaking out of him all night.).

 

OoO~~OoO

 

Half way through breakfast with Bill the next morning Dipper realized that his family had no clue that Bill was now human. And Stan would be coming downstairs in roughly 6 minutes. Fuck. That conversation would not go well and would probably be filled with lots of screaming and maybe a shot gun or two (Stan still believed that guns were less dangerous than ladders), not to mention Bill was wearing a pair of Dipper’s boxers and they were just a tad too small. That, and he would have to call Mable sometime soon, as it was already the last week of May, and she would be coming down to the Shack with Pacifica during the second week of June.

“Bill, how are we gonna tell Stan and Mable about you not being a triangle anymore without any bodily harm becoming involved? Because I’d rather you not get shot.” Dipper said.

“What if you WAKE STAN UP and give him a run down BEFORE he gets down here. Then MAYBE just MAYBE he won’t blow my dick off.”

Unfortunately, Stan had apparently decided to wake up a little early, as the two people in the kitchen could hear the stairs creaking, footsteps soon approaching their current place of standing.

Stan seemed to wander a little into the kitchen before noticing that there was no floating triangle attached to some part of Dipper’s body, a young man replacing its place at Dipper’s side.

Stan pinched the bridge of his nose, pushing his glasses up. “Dipper, please tell me that I don’t have to go get the shot gun.”

Before Dipper could even begin to answer “Hey Stan-Man! It’s ME the TRIANGULAR BEING WITH INFINATE STRENGTH AND NO WEAKNESS THAT ENJOYS FUCKING YOUR NEPHEW!” came from the body beside him.

Dipper smacked his hand to his forehead. Bill always picked the moments that were the worst for his physical health to antagonize Stan.

“… I’m getting the shot gun. Keep him there Dipper.” Stan said, turning around and heading for his office.

Bill, however, made a very high pitched squeak, and ran to hide behind the Sascrotch, only a tuft of his blonde hair poking out above it.  
Meanwhile, Dipper went to talk to Stan about maybe NOT blowing his boyfriend to kingdom come.

“Grunkle Stan! We talked about this! No shooting Bill! Even if he is an annoying little shit! And Mable said no shooting things or magic in the house!” Dipper yelled after him.

“THEN TELL HIM NO MORE TALKING ABOUT SEX INFORNT OF ME!” Stan yelled back.

Dipper sighed. 58th crisis that involved Stan trying to shoot Bill this year avoided.

“Bill! Did you hear that?! No more TMI’ing Stan!” Dipper told the figure hiding behind the tourist attraction (Again).  
Bill’s face peeked out. “So your CRAZY GREAT UNCLE won’t shoot me?”

“No, Bill. Not this time.”

Bill sighed. “GOOD. That shit HURTS! AND IT’S A PAIN TO FIX THE DAMAGE IT CAUSES! Now let’s EAT! This meatsack requires SUSTENANCE.”

Dipper sighed (again) and got out three bowls for cereal (The cooking had really gone downhill in the shack since Mable left. Stan could make Stan cakes and boxed lunches, while Dipper couldn’t cook anything for shit. Last time he tried he burnt water.). Bill launched himself at the table, grabbing the bowl as soon as Dipper had finished, dumping the whole thing over his face, almost chocking on the small bits of Lucky Charms. 

Dipper tried valiantly not to laugh. He ended up failing miserably. The sight of Bill looking slightly startled, covered in milk and Lucky Charms was too funny. Then he realized that he would have to clean it up.

“Damnit Bill!” Dipper said, still laughing hard enough to miss his phone vibrating with a text from Mable.


	4. Chapter 4

**Notes for the Chapter:**

> ok so this chapter is really late, but my tablet broke, and it just so happened to be where I write everything, so I managed to did up an old windows XP computer from storage and I'm posting this from there. Sorry that it's a little shorter than usual, but it really wanted to end there, and it leads up to the next chapter really well, so I'm just gonna leave this here for your enjoyment.  
> Also, if you have any feedback on Mable's character, I would love to hear it, because this is my first time writing a truly cheerful character like her.

From: Mable  
At 9:32  
“Hey broseph! The college caught on fire! I’m ok though, don’t worry! It happened over the weekend during a science lab. But anyways since the main building burnt down, so exams got cancelled!!!!!!!! Anyone who currently had a passing grade passes regardless of exams!!!!!!!!!!!!! WOO! Anyway, Paz and I got tickets for a plane ride up on the 26! A whole 3 weeks early! Can’t wait to help out with the shack again!”

 

From: Dipping Sauce  
At 4:08  
“Holy crap Mable! I can’t believe I’m gonna see you in two days! Glad that you don’t have to suffer through exams. Maybe we should go on one of those old fashioned Mystery Twins adventures? Tell Paz I say hi, ok? See ya soon Mabes :)”

 

From: Dipping Sauce  
At: 4:10  
“Also Bill has a human body now bye.”

 

From: Mable  
At 4:13  
“DIPPER WGHAT?! HOW? WHAT DID YOU DO?”

 

At 4:15  
“DIPPER!?”

At 4:23   
“DIPPER YOU CANT SAY SOMETHING LIKE THAT AND THEN LEAVE!”

 

At 4:30  
“DIIIIIIIIIIIIIIIIIIIIIIIIIPPPPPPPPPPPPPPPPPPPPPPPPEEEEEEEEEEEEEEEEEEEEEEEEEEEERRRRRRRRRRRRRR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!”

 

At 4:42  
“I swear Dipper I will text Bill and I will tell him youre being a huge butt!”

 

Calling: Mable  
“DIPPER! WHAT DID YOU DO AND HOW DID YOU DO IT?!”

“Jesus, Mable ok! Just don’t text Bill (Dipper remembered getting Bill a smart phone. All was fine and well for a while; he figured out how to text and call the two people in his contact list. Then Bill found the porn, which lead him to discover social media in some weird and convoluted way, and now Bill had a blog that was strangely popular.)

“So… umm… Bill and I decided to… uh…”

“Dipper! You’re killing me! Just spit it out!”

“We uh… wedecidedtotryforkids so-”

“AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!”

“I forgot you did the multiple exclamation points in real life too…”

“KIDS DIPPER! KIDS! SMALL YOU AND BILLS! AAAAAAAAAAAAAAAA! Wait how would that even work? I mean you’re both guys well Bill is technically an interdimensional dream demon who, by the way, is a floating triangle but anyways how?”

“So believe it or not, it was Bill who suggested we try for kids, and I agreed. Figured I was ready, you know? But anyways, I asked that too, and that was what lead to the discovery that Bill could make a new body from scratch. One with female reproductive organs and genitals and everything, but a male body other than that, and that yes, kids that were biologically ours were in fact possible. Though, I may ask you to give Bill a sex-ed lesson because he freaked out during sex when he found out that girls’ parts produce that natural lube stuff.”

“Ok Broseph. One: that was a little TMI. I don’t need to know about your sex life with Bill. Two: why don’t you just wait and tell him when he starts bleeding down there.”

“Because, Mable, I don’t want to deal with a Bill who thinks that he did something wrong. Remember the time he hid behind the Sascrotch for a week and you had to bring him plates of carrot sticks that he couldn’t even eat because he thought I found him weird? You would have to do that again until he figures out that bleeding from a vagina is a normal occurrence. I’d rather have a really awkward conversation about it with him than have to coax him out from behind various tourist attractions.”

“Point. What if I just brought over one of my old ‘How Puberty Works for Girls’ books and had him read that?”

“Mabes you are a genius.”

“Thanks Dippin’ Dot. I try.”

“See you in two weeks, Miss creative Genius.”

“See ya soon Dipper!”

 

Call Ended

 

Dipper sighed. He really should have thought about the fact that Bill really doesn’t know a lot about how human bodies work outside of how they survive. This was going to be a lot harder than he thought. Dipper could either procrastinate on telling Bill about general female reproduction for two days until Mable got there and would kindly pressure him into doing it for his own good, or he could do this his way and get it over with. Dipper really did not want to have to pull Bill from behind the Sascrotch again, so Dipper figured that it would be better to talk to Bill about female reproduction sooner rather than later. He also had to let Stan know that Mable was coming down a lot sooner than they had expected. Dipper thought that he should probably leave out the part where the college burned down. He’ll just tell Stan that exams had been moved up.

Where was Stan Anyways? Eh. Yelling in the shack was common.

“HEY STAN!”

“WHAT?”

“MABLE SAYS THAT EXAMS GOT MOVED UP AND SHE’S GONNA BE HERE IN TWO DAYS!”

Dipper heard a series of crashes come from somewhere in the gift shop before Stan skidded into view. He really moved fast for an old dude.  
“What? Dipper you said something about Mable?” Stan asked.

“Yeah, Grunkle Stan. Mabel says that her exams got moved up a bunch of weeks, so she’s gonna be here in 2 days.”

Another loud crash was heard from upstairs before Bill’s face appeared around the corner of the stairs.

“Shooting Star is coming sooner than planned?! She said she was going to bring me a sweater! Wonder if it will still fit? BY THE WAY, Pine Tree, did you tell Shooting Star about…THIS?” Bill said, gesturing at himself.

Dipper sighed for what felt like the 20th time that day. “Yeah. Mable’s coming in a couple of days, so we should get her room ready. Bill, I did tell her about our plans, so Mabes is all caught up.”

Stan looked about to ask what ‘plans’ Dipper and Bill had been concocting, but Dipper beat him to it. “Grunkle Stan, you probably don’t want to know.”

Stan just raised his hands in surrender and walked out of the room, having earned what he needed to.

“I’ll go get Mable’s room ready.” Dipper said.

 

OoO~~ 2 days later ~~OoO

 

2 days later, on May 26, 3:26pm, there was a knock on the Mystery Shack’s door. Even Dipper, who was two feet away after getting a bowl of Lucky Charms from the kitchen, couldn’t beat Bill’s teleportation.

Bill literally tore the door off of its hinges (and left it lying on the floor), revealing the shocked young woman standing in the doorway. 

“SHOOTING STAR! How GOOD OF YOU to show up!” Bill pulled Mable into a tight hug, twirling her around twice, before setting her on the once upright door.  
“SO! Did you bring that my new sweater? Did ya, did ya, did ya?” Bill asked, bouncing a little, almost like a puppy.

Dipper watched on in amusement. There were very few things that made Bill this excited. Torture, Mabel Sweaters, sex, harassing Stan, world domination, Dipper, and pain were the seven (how ironic) things that tended to make Bill giddy on a regular basis (Bill did have to resize all of his Mable Sweaters since he got his new body).  
Bill seemed to vibrate as Mable reached into her suitcase and, with a flourish, pulled out a tiny yellow sweater with the words ‘Dorito Demon’ stitched in black with a picture of triangle Bill in between them. Small Doritos littered the sleeves, while a brick pattern made up the lowest quarter of the sweater. 

Bill promptly removed the sweater that he was currently wearing (which said ‘Ilumi-NAUGHTY’ stitched in black bubble letters on it) and threw it at Dipper (who managed to save it from the bowl of Lucky Charms that he was still holding) before donning his new sweater. 

“Bill!” Mable admonished softly. “What have I told you about throwing things at Dipper? You know he can’t catch anything!” Mable said, observing Dipper accept his fate as a human sweater rack.

“Thanks for the vote of confidence, Mabes.” Dipper said sarcastically.

“Aw, Dip! You know we love you!”

Dipper could almost hear the smiley face emoji in Mable’s voice.

The next thing Dipper knew, he was being pulled into a hug that smelled like paint, edible glitter, and cupcakes. Mable hugs were the best (despite being a morally gray, anti-social, 20 something year old writer/mystery hunter/business owner, he loved all kinds of intimate cuddling. Mable currently had about 15 different photos of Dipper falling asleep on random people, namely Grunkle Stan, Wendy, Soos, Pacifica, and a whole bunch of Dipper falling asleep with Bill wrapped in his arms and shirt. Since Mabel found out that Bill had a human form, she was incredibly eager to get one of Dipper falling asleep on Bill. Little did Mable know that Bill had already been used as a pillow multiple times in the two days that he had had this form.).  
\  
Dipper laughed under the sweater that was still covering his face, and hugged his twin back, unfortunately spilling the bowl of Lucky Charms all over the two of them.  
Bill apparently found this hilarious.

“Bill! We were having a moment!” Mable cried.

“Well, it IS my job to make mortals unhappy.”

“That is no good reason to ruin my moments Bill Cipher!” Mable replied, before moving away from Dipper and smacking Bill upside his head.  
Mable sighed. “I’m gonna go tell Grunkle Stan that I’m home. Then we can watch a crap ton of old movies and eat candy ‘till we BARF!”  
Bill threw his hands in the air. “WOO! PUKING! You NEVER cease to amaze me Shooting Star!”

Dipper laughed at his boyfriend’s actions.

“I’m gonna go make sure he doesn’t hurt himself, you go say hi to Stan. He should be down in his work area.” Dipper shooed Mabel towards the gift shop, before going to check on Bill.

Bill was already sitting on the couch, surrounded by what Dipper figured was roughly 30 bags of assorted skittles and Maynard’s gummies.

“God Damnit Bill!”


	5. Chapter 5

**Notes for the Chapter:**

> Ok. New chapter. Finally! I’ve been writing a bunch for this in a notebook in the absence of a computer, so hopefully these chapters can be up soon, but don’t count on it because exams are coming up and school is a bitch. Side note: in this chapter we have period stuff, and I have based this off of my experiences of being in lots of pain, then being really fucking horny, so if this isn’t what other girls feel, then sorry, but this is how I wrote it. This chapter is also roughly 500 words over the usual length because of added sex! Hope you enjoy!
> 
> THIS CHAPTER HAS CREATED SOME NEW TAGS!!!!!!!! IF PERIOD SEX SQUICKS YOU OUT YOU SHOULD LEAVE THE END OF THIS CHAPTER ALONE. You have now been warned. Twice. By both the tags and me, so any COMPLAINTS in the comments about THIS PARTICULAR TOPIC WILL HOLD NO ARGUMANTAL VALUE.

It was 11:00 and Dipper was the most comfortable that he had been in a while. Bill was watching old reruns of Duck-tective with his head in Dipper’s lap, while Mable had fallen asleep with her head on Dipper’s thigh.

Dipper snorted as the character on screen ran off and reappeared with a cartoonishly large armful of weapons.

“What ‘re you laughing about, Pine Tree?”

“Just the first time I let you into the Shack.”

 

“Killing that Gryphon was fun.”

“Stan yelling at you was fun.”

That horrific event took place the summer Dipper and Mable turned 14. Dipper had been researching Sirens when it all began.

 

OoO~~Flashback~~OoO

 

Dipper was calmly sitting at his desk, reading up on Sirens when something ran into the side of the shack. Then a Gryphon threw its self past Dipper’s window.

“Oh shit! Bill!”

Dipper screamed a little when Bill thunked against his window. Dipper hurried to open it.

“Right. Glass. Glass is a thing.” Bill muttered. “Hey Pine Tree. What’s you-oh. GRYPHON ON YOUR HOUSE. Do I need to do anything?”

Dipper huffed. “I don’t know, Bill. Do you?”

“I’ll take your sarcasm as a yes. Wanna invite me in?”

“Why do I have to?”

“You want me to do something to protect you, you have to invite me in. Your REDICULOUS UNCLE just HAD to place an ABSURD AMOUNT OF PROTECTIONS on this place. Though WHY ON EARTH is there a LARGE ANGRY GRYPHON TRYING TO RIP THE ROOF OFF?!”

“Ok, one: I, Dipper Pines allow Bill Cipher to enter this household. Two: I tripped into it while being chased by Pixies and I disturbed the nest.”  
Bill floated into the Shack, hands full of blue fire. There was an indignant squawk and an explosion of feathers before the weight on the roof disappeared. Dipper sighed in relief.

Minutes later, footsteps sounded on the stairs and Stan burst into the room.

“Cipher! How the hell did you get in here?!” Stan yelled.

“WO HO! Heya Fez! Pine Tree here let me in!”

“Dipper! Why the FUCK did you let BILL CIPHER in?!”

“Well there WAS a Gryphon tearing our roof off, Bill’s been a good friend for years, despite thinking that screaming heads are good gifts- “

Dipper was interrupted by an indignant “Hey! That was a great idea!” from Bill floating next to him.

“No, it wasn’t. And Bill also got the Gryphon off of the shack with absolutely no catch. Is that what you want to hear?”

“Well then. I’d love to hear that my nephew WASN’T hanging around a floating triangle, but I can’t stop you. I will; however, ask that you two keep to the attic and the woods where the destruction of my things WILL be kept to a minimum.”

Dipper sighed, happy that his Grunkle wasn’t going to do something stupid. “Yeah. I think that we can work with that. What do you think, Bill?”

“WELL, I REALLY wasn’t expecting Fez here to actually LET ME NEAR HIS ONLY NEPHEW without a fight, though I GUESS the Gryphon could count as one…ANYWAY! Yeah. I’m cool with that.”

“Good. Now, I’m gonna go fix that goddamned sign for the thousandth time.”

Bill snapped his fingers. “I got it covered this time, Fez.”

Stan nodded and walked out of the room.

 

OoO~~End Flashback~~OoO

 

“Heh. I was surprised that you didn’t get Stan’s infamous shovel talk then and there.”

Bill smiled. “Yeah. That happened later.”

 

OoO~~Flashback~~OoO

 

“YOU’RE WHAT?!” Stan bellowed.

“I’m dating Bill Cipher.” Dipper stated with as plain a face as he could muster.

“Kid… Why Bill Cipher? Why not a Vampire? Or a Ghost? Even that bunch of Gnomes your sister dated is better than Bill freaking Cipher!” Stan sighed. What the hell was he going to do with this kid? He was only 16 and he was dating a goddamned dream demon! It’s not like he could do anything about it though. The kid was way too  
stubborn. Even if he put the kid on lockdown, Dipper would find a way to see the damn thing on his own. 

Welp! Time to shovel talk a demon and hope he doesn’t die trying.

“Well. Bring in Mr. Floating Nacho. I wanna talk.”

“Ok…” Dipper began hesitantly. “But just talking right? And you won’t do anything stupid?”

“Yeah. Sure thing kid. Bring on the demon.”

Dipper sighed. This could either end very well, or Stan was toast; and if Stan did anything to piss Bill off, there was really nothing Dipper could do to help him.

“Here goes nothing. Hey Bill? Could you come over for a little bit?”

There was a small pop before Dipper felt a weight settle on the brim of his hat, small black legs hanging down. “Hey kid. What seems to be the- oh. Did you tell Fez?”

“Yup.”

“And how’s he taking it?”

“Better than I originally thought. You’re still getting the shovel talk though.”

“Damn straight!” Stan interjected.

“Fuck me.”

“Ok Cipher. You’ve done some pretty nasty shit. But, you are a demon, so it is your job, and you seem to not be treating my nephew like shit. BUT! Of you hurt Dipper in any way, I will personally hunt you down, bind you, let Mable and her girlfriends use you as a dress-up doll, before exorcising you from every. Single. Plane. Of existence. Twice. Even if it kills me. Are we clear?”

Dipper felt Bill “stand” on his head. “Sir, yes sir!” Bill said, full of conviction and a mock salute.

“Good. No sex for a year.”

“Aw c’mon Fez! Really?” Bill whined. Dipper tried not to laugh. It was a bit late for the ‘no sex’ idea.”

“I mean it Cipher!”

“Fuck.”

 

OoO~~End Flashback~~OoO

 

“And when Mabel walked in at the end! Hah! I’m actually really glad we had already told her. She would have killed us if she wasn’t the first one to know.” Dipper said, his sentence punctuated by a yawn. 

“Yeah. Shooting Star can be very chaotic.” Bill looked at Mabel’s sleeping form. “Maybe we should take her upstairs.”

“Yeah, sure. I’m gonna sleep too. The movies are over anyways.”

Once Bill had floated Mabel into her room, and tucked into bed, he headed to his and Dipper’s room to do the same for Dipper. Once Bill had done this, it took not two minutes for both boy and demon to fall asleep.

 

OoO~~3 Weeks Later~~OoO

 

3 weeks later, Bill burst into the kitchen with a blood covered hand.

“Dipper! Dipper look! I’m bleeding!”

Dipper sighed. “Did you stab yourself with Mabel’s sewing pins AGAIN? I thought I told you not to do that! And if this is about sex, kinks stay in the bedroom Bill. You know that!”

Mabel looked horrified. “You used my sewing pins for sex?!” She screamed.

“No, silly!” Bill continued, ignoring Mabel’s comment completely. “I’m bleeding from my lady bit! That means something for human females, right? What does it mean?”  
Bill said, shoving his bloody hand into Dipper’s face.

“Oh shit! Mabel, we forgot to give Bill the sex talk!”

“Aw crap. And you guys USED MY SEWING PINS FOR SEX?!”

“No, Bill used your sewing pins for sex. I bought you new ones’ every time after. Even though I BOUGHT A SET SPECIFICALLY FOR THAT PURPOSE. And we still have to give Bill the sex talk.”

“But Dipppeeeeeeer! I already know how sex works!” Bill whined.

“Yeah. But do you understand how human reproduction works?”

“Of course! Dipper sticks his thing in me and sperm makes a baby. Easy and fun!”

“It’s a lot more complicated than that, Bill. Girls bleed out of their vaginas for around a week, give or take a few days, every month. This is because girls’ bodies put an egg in her uterus once every month, and if the egg isn’t fertilized by their partner’s sperm, it, and the uterine lining is shed via the vaginal opening, which is why you’re currently bleeding from your crotch.” Mabel explained.

“Oh. So human females ovulate on a monthly cycle?” Bill asked.

“yeah.”

“Ok. So this was part of letting my body adjust?”

“Pretty much.” Dipper replied.

Bill pulled out a chair and sat down. “So! What’s for lunch?” Bill said, waving his bloody hand around.

Dipper laughed. “Ew! Bill! Go wash your hand! I do NOT want blood in my food. Period!”

Mabel groaned. “Dipper you little shit! That was worse than one of Grunkle Stan’s.”

Dipper laughed while Bill got up, grumbling about how humans don’t understand the nutritional value of blood, and washed his hand.

Suddenly, Mabel smacked her forehead. “I forgot about pads and tampons! How could I forget about pads and tampons?!”

“What the fuck are pads and tampons, Shooting Star?”

“Tampons go up your vagina to make sure you don’t bleed through your cloths and onto things you sit on. Pads do the same thing, but they stick to your panties instead of going up your vag.” Mable explained.

“Jesus.”

“Ok, you two have fun, I’m gonna run to the store!”

Bill smirked. “We’ll have PLENTY of fun, Shooting Star.”

“No more sex on the couch!” Mable called through the door.

“So…” Bill said, once they heard the car drive away. “Sex on the couch?”

“Bill, period sex is really messy. If we were gonna have sex anywhere right now, it would have to be the shower.”

“So. Shower sex?”

“Fuck yes. Let’s go!”

“Go where?”

Bill groaned. “Stan, you are the WORST cock block.”

“No sex on my couch! And I do NOT want to hear about it later! I’ll be in the basement.”

 

OoO~~2 Days Later~~OoO

 

When Dipper woke up, he was alone; which wasn’t that unusual (Since Bill liked to get up at the ass crack of dawn to go terrorize the creatures in the Gravity Falls forest for a bit. Sometimes Dipper would tag along. It was fun to launch some gnomes into the sunrise.). What WAS unusual was finding Bill faceplanted into the couch, groaning and hissing various different expletives in various different languages. Dipper recognized some as Latin, others as French or German. Bill looked really fucking miserable.

Dipper approached slowly, not wanting to startle the demon. “Bill?” Dipper said, gently setting his hand on the demon’s shoulder.  
Dipper had never seen Bill move as fast as he did then. Within 10 seconds, Bill had wrapped himself around Dipper and they were lying on the couch. Bill had his face  
pressed into Dipper’s neck, hands gripping his shirt. Dipper wrapped his arms around the apparently distraught demon.

“Bill? Are you ok?”

“It hurts Dipper. And not the good kind either. This is Evil Hurt Pine Tree.”

Dipper sighed. Mable had said the same thing whenever it was her ‘time of the month’. “Ok Bill. Is this a kind of gradual throbbing in your abdomen, or something else?”

Bill winced a little. “Abdomen.”

Ok so it was probably just period cramps. Dipper could deal with that. What did Mable always say worked? Heat? Yeah. That was it.

“Hey Bill, let’s go up and take a hot bath. Mable says that those always work to get rid of cramps.”

Bill nodded, but remained plastered to Dipper’s front.

“Are you gonna make me carry you all the way upstairs?”

“Yes.” Bill said, full of conviction.

Dipper sighed. What wouldn’t he do for his demon?

 

OoO~~OoO

 

It was moments like this that Dipper was glad that climbing trees and running to get the hell away from some particularly vicious monsters had given him some pretty decent muscles and endurance.

Once Dipper had gotten Bill into the bathroom, he set Bill on the toilet seat, and started the water to fill up the bathtub.

Once the bathtub was filled enough so that two people could sit comfortably in it without the water overflowing, Dipper and Bill stepped in, Dipper leaning against the back of the tub with Bill lying on his chest.

 

OoO~~OoO

 

Dipper had no idea of how much time had passed, but eventually, he felt Bill start to move around. Then he felt lips press against his. It took Dipper a second to process what exactly was happening, but once he did, Dipper found himself to be quite eager to participate.

Eventually, the two had to break the kiss to breath. They leaned their foreheads together. Then Bill opened his mouth.

“Dipper Pines, I need you to FUCK ME SO HARD that we wake up Shooting Star. Ok maybe not that hard, but you get the picture, Pine Tree.”

“Fuck yes. Go grab a towel to put on the mattress.”

Dipper stood up and pulled the plug to drain the water, while Bill ran to get the towel and some lube.

Once Bill returned with the needed items, Dipper found himself grabbed, and teleported onto their bed, with Bill on top of him, eager to begin.

The two shuffled around on the bed for a little, getting the towel spread out (Blood was hard to clean out, damnit! And Bill just HAD to have black and yellow patterned  
sheets that were mostly yellow.). After that was done, Dipper soon found himself flat on his back, with a REALLY horny demon attacking his face.

Dipper ran his fingers over Bill’s chest, pulling harshly on his nipples. Bill moaned into the kiss, biting at Dipper’s lip, before pulling away to mouth at his human’s chest.

“Mmmmmn. Bill… Hand me the lube, would you?”

Bill grabbed Dipper’s hand, placing it over his vagina, which was already wet enough to forgo lube.

Dipper groaned. That was kinda hot.

Bill pulled Dipper’s hand away from himself, eyeing the blood covered hand hungrily, before running his tongue up Dipper’s palm, catching any drips of blood that had fallen, quickly moving on to suck the blood form each of Dipper’s fingers.

Dipper eventually pulled his hand away from the demon’s mouth, moving it instead, to finger Bill’s entrance.

Bill moaned. “Shall we-Ahh! Get on with it, Pine Tree?”

Dipper pressed on Bill’s shoulders, pushing Bill down onto the bed, flipping their positions.

“I do believe we shall.” Dipper said, using one hand to gently guide himself into Bill, both demon and boy moaning at the sensation.

Dipper paused for a moment, letting Bill adjust to the feeling of something inside of him, before pulling out and sliding back in again.

The two soon found a rhythm, Bill’s legs wrapping around Dipper’s back, hands gripping at shoulders, mouths meeting in messy, passionate kisses.

“Mmmn! Pine Tre-Ah! ‘M close!” Bill moaned into Dipper’s neck.

“Fuck… Me to!” Dipper groaned in response, leaning up to bite at his demon’s neck, earning himself a gasp from Bill.

“Je-esus! Pine Tree! I’m coooh-ming!”

Dipper felt Bill clench around him, a familiar heat building in his lower abdomen.

“Mmmn! Cumming!” Dipper said, his orgasm quickly overtaking him in a wash of pleasure.

Both collapsed on the bed, drowning in a shared post-sex high, eventually forced to get up by blood, semen and various other bodily fluids clinging to them.

Once both were clean and laying comfortably on the bed, Bill rested his head on an elbow and looked Dipper dead in the eye. “So… Pine Tree. Would you say that you 

just fucked me with your mini pine tree?”

“God damnit Bill!”


	6. AUTHORS NOTE

Ok, so I feel a little bad for doing the Dreaded Authors Note thing, but I feel like I should let you guys know what's going on, and why I STILL haven't updated like 3 months later. So, first, I will admit that I lost a lot of my inspiration for this story. My muse literally threw its self out of a 20 story window, only to come crawling back a couple months later. THEN my tablet (which is where I do all of my writing) decided to cop out on me when I was almost done typing and editing, and I ended up having to clear off my hard drive of all of my files, and I hadn't backed up this new chapter, so now I have to do it ALL OVER AGAIN. Then, about a week ago, literally THE DAY AFTER MY TABLET BROKE, my detachable keyboard stopped working. This is the THIRD one that has broken on me due to no fault of my own, and I'm sorry, but I am NOT typing 2000+ words on a touchscreen. That would not be good for my frustration levels. 

Anyways, I'm NOT giving up on this story! I will be writing it on paper while I wait to either get this keyboard fixed, or get a new one. I really hope to have the new chapter up within a few months, if not sooner, but depending on school, technology, and the muse, it may take longer. I'm so sorry, but life has kinda kicked me in the ass.

Thanks for putting up with my erratic publishing! 


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